For example, JP2008-290625A discloses a seat slide apparatus for a vehicle. The vehicle is a so-called three-row seat vehicle having a front seat, a second-row seat and a third-row seat, in which a lower rail fixed on a vehicle floor with extending in the front-rear direction of the vehicle is mounted in a range corresponding to normal positions of the second-row and third-row seats. An upper rail, which is fixed to the second-row seat and is configured to move along the lower rail, is provided to move over a wide range (range corresponding to the normal positions of the second-row and third-row seats) in the front-rear direction of the vehicle.
There is a so-called three-row seat vehicle in which the vehicle floor is bent between the normal position of the front seat and the normal position of the second-row seat, and a rear side thereof is inclined,. However, in the related seat slide apparatus for a vehicle, a planar vehicle floor is generally assumed, so that the lower rail is linearly designed. The design is not corresponding to the bending (inclination) of the vehicle floor, and a problem, which occurs when the lower rail including the bent part is provided, is not considered at all. In a related seat slide apparatus for a vehicle in which the lower rail is provided to avoid the bent part, a problem occurs in that the degree of moving freedom of the front seat in the front-rear direction is to be limited.
A need thus exists for a seat slide apparatus for a vehicle which is not susceptible to the drawback mentioned above.